Biosynthesis of optically active Diels–Alder type adducts revealed by an aberrant metabolism of O-methylated precursors in Morus alba cell cultures

Abstract

Addition of O-methylated chalcone, as precursors, to Morus alba cell cultures has resulted in the formation of optically active O-methyl derivatives of chalcomoracin (1) and kuwanon J (2), corroborating the pivotal step of the biosynthesis of (1) and (2) to be the enzymic Diels–Alder reaction.